Systems and methods for directional mesh networks with joint backhaul and access link design

ABSTRACT

A cellular communications network may be configured to leverage a millimeter wave (mmW) mesh network. Base stations may be configured to operate as mmW base stations (mBs). Such base stations may be configured to participate in the mmW mesh network and to access the cellular communications network (e.g., via cellular access links). A network device of the cellular communications network (e.g., an eNB) may operate as a control entity with respect to one or more mBs. Such a network device may govern mesh backhaul routing with respect to the cellular communications network and the mmW mesh network. Such a network device may configure the mmW mesh network, for example by performing a process to join a new mB to the mmW mesh network. A WTRU may send and receive control information via a cellular access link and may send and receive data via the mmW mesh network.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent applicationnos. 61/645,352, filed May 10, 2012, and 61/645,156, filed May 10, 2012,both of which are incorporated herein by reference in their entireties.

BACKGROUND

In recent years demand for cellular network bandwidth has steadilyincreased. Increases in cellular network bandwidth demand are predictedto continue, for instance in accordance with capabilities of LTE and/orLTE advanced networks that offer significantly higher data transmissionrates. Within the radio frequency spectrum typically reserved forcellular network communications, ensuring that there is sufficientbandwidth to enable efficient and reliable communications across thesewireless communications networks, for instance sufficient fortransporting video, continues to be challenging. For instance, the rapidadoption of smart phones that are capable of generating and displayingvideo may place additional demands on these wireless communicationnetworks.

SUMMARY

One or more base stations of a cellular communications network may beconfigured to operate as millimeter wave (mmW) base stations (mBs). SuchmBs may be configured to participate in an mmW mesh network and toaccess the cellular communications network, for example via cellularaccess links. Example configurations of mBs may be enabled by interfacesamong the nodes in accordance with different node deployment scenarios.Methods that enable initial startup procedures for such mBs aredisclosed.

A network device of the cellular communications network, for example aneNB, may operate as a control entity with respect to one or more mBs.Such a network device may configure the mmW mesh network, for example byperforming a process to join a new mB to the mmW mesh network. Forexample, such an eNB may assist with the establishment oftransmit-receive beam orientation between one or more mBs, in accordancewith signal levels between the mBs and/or interference levels at one ormore neighboring mBs, for example using cellular layer communications.

Such an eNB network device may govern mesh backhaul routing with respectto the cellular communications network and the mmW mesh network.Cellular connectivity (e.g., cellular access links) may be used toprovide routing information to mBs and/or to collect channel information(e.g., average and/or instantaneous gain information) from the mBs. TheeNB may use such information to govern routing through the cellularcommunications network and the mmW mesh network. A WTRU configured formmW communications may send and receive control information via acellular access link, and may send and receive data via the mmW meshnetwork, for example.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A depicts a system diagram of an example communications system inwhich one or more disclosed embodiments may be implemented.

FIG. 1B depicts a system diagram of an example wireless transmit/receiveunit (WTRU) that may be used within the communications systemillustrated in FIG. 1A.

FIG. 1C depicts a system diagram of an example radio access network andan example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 1D depicts a system diagram of an example radio access network andan example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 1E depicts a system diagram of an example radio access network andan example core network that may be used within the communicationssystem illustrated in FIG. 1A.

FIG. 2 depicts a block diagram of an example deployment of a cellularcommunications system and an associated millimeter wave (mmW)communications system.

FIG. 3 depicts a block diagram of another example deployment of acellular communications system and an associated millimeter wave (mmW)communications system.

FIG. 4 depicts a block diagram of another example deployment of acellular communications system and an associated millimeter wave (mmW)communications system.

FIG. 5 depicts a block diagram of an example deployment of a cellularcommunications system and an associated millimeter wave (mmW)communications system having an mmW gateway node (mGW).

FIG. 6 depicts a block diagram of another example deployment of acellular communications system and an associated millimeter wave (mmW)communications system having an mGW.

FIG. 7 illustrates an example setup procedure for an mmW base station(mB) device in a collocated deployment.

FIG. 8 illustrates an example setup procedure for an mmW base station(mB) device in a non-collocated deployment.

FIG. 9 illustrates another example setup procedure for an mmW basestation (mB) device in a non-collocated deployment.

FIG. 10 depicts a block diagram of an example mB mesh backhaul system.

FIG. 11 depicts a block diagram of an example mmW system with mmW meshbackhaul.

FIG. 12 depicts a block diagram of inputs to an example mesh backhaulrouting protocol (MBRP).

FIG. 13 illustrates an example operational process flow a centralizedMBRP.

FIG. 14 illustrates an example operational process flow a decentralizedMBRP.

DETAILED DESCRIPTION

FIG. 1A is a diagram of an example communications system 100 in whichone or more disclosed embodiments may be implemented. The communicationssystem 100 may be a multiple access system that provides content, suchas voice, data, video, messaging, broadcast, etc., to multiple wirelessusers. The communications system 100 may enable multiple wireless usersto access such content through the sharing of system resources,including wireless bandwidth. For example, the communications systems100 may employ one or more channel access methods, such as code divisionmultiple access (CDMA), time division multiple access (TDMA), frequencydivision multiple access (FDMA), orthogonal FDMA (OFDMA), single-carrierFDMA (SC-FDMA), and the like.

As shown in FIG. 1A, the communications system 100 may include at leastone wireless transmit/receive unit (WTRU), such as a plurality of WTRUs,for instance WTRUs 102 a, 102 b, 102 c, and 102 d, a radio accessnetwork (RAN) 104, a core network 106, a public switched telephonenetwork (PSTN) 108, the Internet 110, and other networks 112, though itshould be appreciated that the disclosed embodiments contemplate anynumber of WTRUs, base stations, networks, and/or network elements. Eachof the WTRUs 102 a, 102 b, 102 c, 102 d may be any type of deviceconfigured to operate and/or communicate in a wireless environment. Byway of example, the WTRUs 102 a, 102 b. 102 c. 102 d may be configuredto transmit and/or receive wireless signals and may include userequipment (UE), a mobile station, a fixed or mobile subscriber unit, apager, a cellular telephone, a personal digital assistant (PDA), asmartphone, a laptop, a netbook, a personal computer, a wireless sensor,consumer electronics, and the like.

The communications systems 100 may also include a base station 114 a anda base station 114 b. Each of the base stations 114 a, 114 b may be anytype of device configured to wirelessly interface with at least one ofthe WTRUs 102 a. 102 b, 102 c, 102 d to facilitate access to one or morecommunication networks, such as the core network 106, the Internet 110,and/or the networks 112. By way of example, the base stations 114 a, 114b may be a base transceiver station (BTS), a Node-B, an eNode B, a HomeNode B, a Home eNode B, a site controller, an access point (AP), awireless router, and the like. While the base stations 114 a, 114 b areeach depicted as a single element, it should be appreciated that thebase stations 114 a, 114 b may include any number of interconnected basestations and/or network elements.

The base station 114 a may be part of the RAN 104, which may alsoinclude other base stations and/or network elements (not shown), such asa base station controller (BSC), a radio network controller (RNC), relaynodes, etc. The base station 114 a and/or the base station 114 b may beconfigured to transmit and/or receive wireless signals within aparticular geographic region, which may be referred to as a cell (notshown). The cell may further be divided into cell sectors. For example,the cell associated with the base station 114 a may be divided intothree sectors. Thus, in one embodiment, the base station 114 a mayinclude three transceivers, i.e., one for each sector of the cell. Inanother embodiment, the base station 114 a may employ multiple-inputmultiple output (MIMO) technology and, therefore, may utilize multipletransceivers for each sector of the cell.

The base stations 14 a, 14 b may communicate with one or more of theWTRUs 102 a. 102 b, 102 c, 102 d over an air interface 116, which may beany suitable wireless communication link (e.g., radio frequency (RF),microwave, infrared (IR), ultraviolet (UV), visible light, etc.). Theair interface 116 may be established using any suitable radio accesstechnology (RAT).

More specifically, as noted above, the communications system 100 may bea multiple access system and may employ one or more channel accessschemes, such as CDMA, TDMA, FDMA, OFDMA, SC-FDMA, and the like. Forexample, the base station 114 a in the RAN 104 and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Universal MobileTelecommunications System (UMTS) Terrestrial Radio Access (UTRA), whichmay establish the air interface 116 using wideband CDMA (WCDMA). WCDMAmay include communication protocols such as High-Speed Packet Access(HSPA) and/or Evolved HSPA (HSPA+). HSPA may include High-Speed DownlinkPacket Access (HSDPA) and/or High-Speed Uplink Packet Access (HSUPA).

In another embodiment, the base station 114 a and the WTRUs 102 a, 102b, 102 c may implement a radio technology such as Evolved UMTSTerrestrial Radio Access (E-UTRA), which may establish the air interface116 using Long Term Evolution (LTE) and/or LTE-Advanced (LTE-A).

In other embodiments, the base station 114 a and the WTRUs 102 a, 102 b,102 c may implement radio technologies such as IEEE 802.16 (i.e.,Worldwide Interoperability for Microwave Access (WiMAX)), CDMA2000.CDMA2000 IX, CDMA2000 EV-DO, Interim Standard 2000 (IS-2000), InterimStandard 95 (IS-95), Interim Standard 856 (IS-856), Global System forMobile communications (GSM), Enhanced Data rates for GSM Evolution(EDGE). GSM EDGE (GERAN), and the like.

The base station 114 b in FIG. 1A may be a wireless router, Home Node B,Home eNode B, or access point, for example, and may utilize any suitableRAT for facilitating wireless connectivity in a localized area, such asa place of business, a home, a vehicle, a campus, and the like. In oneembodiment, the base station 114 b and the WTRUs 102 c, 102 d mayimplement a radio technology such as IEEE 802.11 to establish a wirelesslocal area network (WLAN). In another embodiment, the base station 114 band the WTRUs 102 c, 102 d may implement a radio technology such as IEEE802.15 to establish a wireless personal area network (WPAN). In yetanother embodiment, the base station 114 b and the WTRUs 102 c, 102 dmay utilize a cellular-based RAT (e.g., WCDMA, CDMA2000, GSM, LTE,LTE-A, etc.) to establish a picocell or femtocell. As shown in FIG. 1A,the base station 114 b may have a direct connection to the Internet 110.Thus, the base station 114 b may not be required to access the Internet110 via the core network 106.

The RAN 104 may be in communication with the core network 106, which maybe any type of network configured to provide voice, data, applications,and/or voice over internet protocol (VoIP) services to one or more ofthe WTRUs 102 a, 102 b, 102 c, 102 d. For example, the core network 106may provide call control, billing services, mobile location-basedservices, pre-paid calling, Internet connectivity, video distribution,etc., and/or perform high-level security functions, such as userauthentication. Although not shown in FIG. 1A, it should be appreciatedthat the RAN 104 and/or the core network 106 may be in direct orindirect communication with other RANs that employ the same RAT as theRAN 104 or a different RAT. For example, in addition to being connectedto the RAN 104, which may be utilizing an E-UTRA radio technology, thecore network 106 may also be in communication with another RAN (notshown) employing a GSM radio technology.

The core network 106 may also serve as a gateway for the WTRUs 102 a,102 b, 102 c, 102 d to access the PSTN 108, the Internet 110, and/orother networks 112. The PSTN 108 may include circuit-switched telephonenetworks that provide plain old telephone service (POTS). The Internet110 may include a global system of interconnected computer networks anddevices that use common communication protocols, such as thetransmission control protocol (TCP), user datagram protocol (UDP) andthe internet protocol (IP) in the TCP/IP internet protocol suite. Thenetworks 112 may include wired or wireless communications networks ownedand/or operated by other service providers. For example, the networks112 may include another core network connected to one or more RANs,which may employ the same RAT as the RAN 104 or a different RAT.

Some or all of the WTRUs 102 a, 102 b, 102 c, 102 d in thecommunications system 100 may include multi-mode capabilities, i.e., theWTRUs 102 a, 102 b, 102 c, 102 d may include multiple transceivers forcommunicating with different wireless networks over different wirelesslinks. For example, the WTRU 102 c shown in FIG. 1A may be configured tocommunicate with the base station 114 a, which may employ acellular-based radio technology, and with the base station 114 b, whichmay employ an IEEE 802 radio technology.

FIG. 1B is a system diagram of an example WTRU 102. As shown in FIG. 1B,the WTRU 102 may include a processor 118, a transceiver 120, atransmit/receive element 122, a speaker/microphone 124, a keypad 126, adisplay/touchpad 128, non-removable memory 130, removable memory 132, apower source 134, a global positioning system (GPS) chipset 136, andother peripherals 138. It should be appreciated that the WTRU 102 mayinclude any sub-combination of the foregoing elements while remainingconsistent with an embodiment.

The processor 118 may be a general purpose processor, a special purposeprocessor, a conventional processor, a digital signal processor (DSP), aplurality of microprocessors, one or more microprocessors in associationwith a DSP core, a controller, a microcontroller, Application SpecificIntegrated Circuits (ASICs), Field Programmable Gate Array (FPGAs)circuits, any other type of integrated circuit (IC), a state machine,and the like. The processor 118 may perform signal coding, dataprocessing, power control, input/output processing, and/or any otherfunctionality that enables the WTRU 102 to operate in a wirelessenvironment. The processor 118 may be coupled to the transceiver 120,which may be coupled to the transmit/receive element 122. While FIG. 1Bdepicts the processor 118 and the transceiver 120 as separatecomponents, it should be appreciated that the processor 118 and thetransceiver 120 may be integrated together in an electronic package orchip.

The transmit/receive element 122 may be configured to transmit signalsto, or receive signals from, a base station (e.g., the base station 114a) over the air interface 116. For example, in one embodiment, thetransmit/receive element 122 may be an antenna configured to transmitand/or receive RF signals. In another embodiment, the transmit/receiveelement 122 may be an emitter/detector configured to transmit and/orreceive IR, UV, or visible light signals, for example. In yet anotherembodiment, the transmit/receive element 122 may be configured totransmit and receive both RF and light signals. It should be appreciatedthat the transmit/receive element 122 may be configured to transmitand/or receive any combination of wireless signals.

In addition, although the transmit/receive element 122 is depicted inFIG. 1B as a single element, the WTRU 102 may include any number oftransmit/receive elements 122. More specifically, the WTRU 102 mayemploy MIMO technology. Thus, in one embodiment, the WTRU 102 mayinclude two or more transmit/receive elements 122 (e.g., multipleantennas) for transmitting and receiving wireless signals over the airinterface 116.

The transceiver 120 may be configured to modulate the signals that areto be transmitted by the transmit/receive element 122 and to demodulatethe signals that are received by the transmit/receive element 122. Asnoted above, the WTRU 102 may have multi-mode capabilities. Thus, thetransceiver 120 may include multiple transceivers for enabling the WTRU102 to communicate via multiple RATs, such as UTRA and IEEE 802.11, forexample.

The processor 118 of the WTRU 102 may be coupled to, and may receiveuser input data from, the speaker/microphone 124, the keypad 126, and/orthe display/touchpad 128 (e.g., a liquid crystal display (LCD) displayunit or organic light-emitting diode (OLED) display unit). The processor118 may also output user data to the speaker/microphone 124, the keypad126, and/or the display/touchpad 128. In addition, the processor 118 mayaccess information from, and store data in, any type of suitable memory,such as the non-removable memory 130 and/or the removable memory 132.The non-removable memory 130 may include random-access memory (RAM),read-only memory (ROM), a hard disk, or any other type of memory storagedevice. The removable memory 132 may include a subscriber identitymodule (SIM) card, a memory stick, a secure digital (SD) memory card,and the like. In other embodiments, the processor 118 may accessinformation from, and store data in, memory that is not physicallylocated on the WTRU 102, such as on a server or a home computer (notshown).

The processor 118 may receive power from the power source 134, and maybe configured to distribute and/or control the power to the othercomponents in the WTRU 102. The power source 134 may be any suitabledevice for powering the WTRU 102. For example, the power source 134 mayinclude one or more dry cell batteries (e.g., nickel-cadmium (NiCd),nickel-zinc (NiZn), nickel metal hydride (NiMH), lithium-ion (Li-ion),etc.), solar cells, fuel cells, and the like.

The processor 118 may also be coupled to the GPS chipset 136, which maybe configured to provide location information (e.g., longitude andlatitude) regarding the current location of the WTRU 102. In additionto, or in lieu of, the information from the GPS chipset 136, the WTRU102 may receive location information over the air interface 116 from abase station (e.g., base stations 114 a, 114 b) and/or determine itslocation based on the timing of the signals being received from two ormore nearby base stations. It should be appreciated that the WTRU 102may acquire location information by way of any suitablelocation-determination method while remaining consistent with anembodiment.

The processor 118 may further be coupled to other peripherals 138, whichmay include one or more software and/or hardware modules that provideadditional features, functionality and/or wired or wirelessconnectivity. For example, the peripherals 138 may include anaccelerometer, an e-compass, a satellite transceiver, a digital camera(for photographs or video), a universal serial bus (USB) port, avibration device, a television transceiver, a hands free headset, aBluetooth® module, a frequency modulated (FM) radio unit, a digitalmusic player, a media player, a video game player module, an Internetbrowser, and the like.

FIG. 1C is a system diagram of an embodiment of the communicationssystem 100 that includes a RAN 104 a and a core network 106 a thatcomprise example implementations of the RAN 104 and the core network106, respectively. As noted above, the RAN 104, for instance the RAN 104a, may employ a UTRA radio technology to communicate with the WTRUs 102a, 102 b, 102 c over the air interface 116. The RAN 104 a may also be incommunication with the core network 106 a. As shown in FIG. 1C, the RAN104 a may include Node-Bs 140 a, 140 b, 140 c, which may each includeone or more transceivers for communicating with the WTRUs 102 a, 102 b,102 c over the air interface 116. The Node-Bs 140 a, 140 b, 140 c mayeach be associated with a particular cell (not shown) within the RAN 104a. The RAN 104 a may also include RNCs 142 a, 142 b. It should beappreciated that the RAN 104 a may include any number of Node-Bs andRNCs while remaining consistent with an embodiment.

As shown in FIG. 1C, the Node-Bs 140 a, 140 b may be in communicationwith the RNC 142 a. Additionally, the Node-B 140 c may be incommunication with the RNC 142 b. The Node-Bs 140 a, 140 b, 140 c maycommunicate with the respective RNCs 142 a, 142 b via an Iub interface.The RNCs 142 a. 142 b may be in communication with one another via anIur interface. Each of the RNCs 142 a, 142 b may be configured tocontrol the respective Node-Bs 140 a, 140 b, 140 c to which it isconnected. In addition, each of the RNCs 142 a, 142 b may be configuredto carry out or support other functionality, such as outer loop powercontrol, load control, admission control, packet scheduling, handovercontrol, macrodiversity, security functions, data encryption, and thelike.

The core network 106 a shown in FIG. 1C may include a media gateway(MGW) 144, a mobile switching center (MSC) 146, a serving GPRS supportnode (SGSN) 148, and/or a gateway GPRS support node (GGSN) 150. Whileeach of the foregoing elements is depicted as part of the core network106 a, it should be appreciated that any one of these elements may beowned and/or operated by an entity other than the core network operator.

The RNC 142 a in the RAN 104 a may be connected to the MSC 146 in thecore network 106 a via an IuCS interface. The MSC 146 may be connectedto the MGW 144. The MSC 146 and the MGW 144 may provide the WTRUs 102 a.102 b, 102 c with access to circuit-switched networks, such as the PSTN108, to facilitate communications between the WTRUs 102 a. 102 b, 102 cand traditional land-line communications devices.

The RNC 142 a in the RAN 104 a may also be connected to the SGSN 148 inthe core network 106 a via an IuPS interface. The SGSN 148 may beconnected to the GGSN 150. The SGSN 148 and the GGSN 150 may provide theWTRUs 102 a, 102 b, 102 c with access to packet-switched networks, suchas the Internet 110, to facilitate communications between the WTRUs 102a, 102 b, 102 c and IP-enabled devices.

As noted above, the core network 106 a may also be connected to thenetworks 112, which may include other wired or wireless networks thatare owned and/or operated by other service providers.

FIG. 1D is a system diagram of an embodiment of the communicationssystem 100 that includes a RAN 104 b and a core network 106 b thatcomprise example implementations of the RAN 104 and the core network106, respectively. As noted above, the RAN 104, for instance the RAN 104b, may employ an E-UTRA radio technology to communicate with the WTRUs102 a, 102 b, and 102 c over the air interface 116. The RAN 104 b mayalso be in communication with the core network 106 b.

The RAN 104 b may include eNode-Bs 170 a, 170 b, 170 c, though it shouldbe appreciated that the RAN 104 b may include any number of eNode-Bswhile remaining consistent with an embodiment. The eNode-Bs 170 a, 170b, 170 c may each include one or more transceivers for communicatingwith the WTRUs 102 a, 102 b, 102 c over the air interface 116. In oneembodiment, the eNode-Bs 170 a, 170 b, 170 c may implement MIMOtechnology. Thus, the eNode-B 170 a, for example, may use multipleantennas to transmit wireless signals to, and receive wireless signalsfrom, the WTRU 102 a.

Each of the eNode-Bs 170 a, 170 b, 170 c may be associated with aparticular cell (not shown) and may be configured to handle radioresource management decisions, handover decisions, scheduling of usersin the uplink and/or downlink, and the like. As shown in FIG. 1D, theeNode-Bs 170 a, 170 b, 170 c may communicate with one another over an X2interface.

The core network 106 b shown in FIG. 1D may include a mobilitymanagement gateway (MME) 172, a serving gateway 174, and a packet datanetwork (PDN) gateway 176. While each of the foregoing elements isdepicted as part of the core network 106 b, it should be appreciatedthat any one of these elements may be owned and/or operated by an entityother than the core network operator.

The MME 172 may be connected to each of the eNode-Bs 170 a, 170 b. 170 cin the RAN 104 b via an S1 interface and may serve as a control node.For example, the MME 172 may be responsible for authenticating users ofthe WTRUs 102 a, 102 b, 102 c, bearer activation/deactivation, selectinga particular serving gateway during an initial attach of the WTRUs 102a, 102 b, 102 c, and the like. The MME 172 may also provide a controlplane function for switching between the RAN 104 b and other RANs (notshown) that employ other radio technologies, such as GSM or WCDMA.

The serving gateway 174 may be connected to each of the eNode Bs 170 a,170 b, 170 c in the RAN 104 b via the S1 interface. The serving gateway174 may generally route and forward user data packets to/from the WTRUs102 a, 102 b, 102 c. The serving gateway 174 may also perform otherfunctions, such as anchoring user planes during inter-eNode B handovers,triggering paging when downlink data is available for the WTRUs 102 a,102 b, 102 c, managing and storing contexts of the WTRUs 102 a, 102 b,102 c, and the like.

The serving gateway 174 may also be connected to the PDN gateway 176,which may provide the WTRUs 102 a. 102 b, 102 c with access topacket-switched networks, such as the Internet 110, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and IP-enableddevices.

The core network 106 b may facilitate communications with othernetworks. For example, the core network 106 b may provide the WTRUs 102a, 102 b, 102 c with access to circuit-switched networks, such as thePSTN 108, to facilitate communications between the WTRUs 102 a, 102 b,102 c and traditional land-line communications devices. For example, thecore network 106 b may include, or may communicate with, an IP gateway(e.g., an IP multimedia subsystem (IMS) server) that serves as aninterface between the core network 106 b and the PSTN 108. In addition,the core network 106 b may provide the WTRUs 102 a, 102 b, 102 c withaccess to the networks 112, which may include other wired or wirelessnetworks that are owned and/or operated by other service providers.

FIG. 1E is a system diagram of an embodiment of the communicationssystem 100 that includes a RAN 104 c and a core network 106 c thatcomprise example implementations of the RAN 104 and the core network106, respectively. The RAN 104, for instance the RAN 104 c, may be anaccess service network (ASN) that employs IEEE 802.16 radio technologyto communicate with the WTRUs 102 a, 102 b, 102 c over the air interface116. As described herein, the communication links between the differentfunctional entities of the WTRUs 102 a, 102 b. 102 c, the RAN 104 c, andthe core network 106 c may be defined as reference points.

As shown in FIG. 1E, the RAN 104 c may include base stations 180 a, 180b, 180 c, and an ASN gateway 182, though it should be appreciated thatthe RAN 104 c may include any number of base stations and ASN gatewayswhile remaining consistent with an embodiment. The base stations 180 a,180 b. 180 c may each be associated with a particular cell (not shown)in the RAN 104 c and may each include one or more transceivers forcommunicating with the WTRUs 102 a. 102 b, 102 c over the air interface116. In one embodiment, the base stations 180 a, 180 b, 180 c mayimplement MIMO technology. Thus, the base station 180 a, for example,may use multiple antennas to transmit wireless signals to, and receivewireless signals from, the WTRU 102 a. The base stations 180 a. 180 b,180 c may also provide mobility management functions, such as handofftriggering, tunnel establishment, radio resource management, trafficclassification, quality of service (QoS) policy enforcement, and thelike. The ASN Gateway 182 may serve as a traffic aggregation point andmay be responsible for paging, caching of subscriber profiles, routingto the core network 106 c, and the like.

The air interface 116 between the WTRUs 102 a, 102 b, 102 c and the RAN104 c may be defined as an R1 reference point that implements the IEEE802.16 specification. In addition, each of the WTRUs 102 a, 102 b, 102 cmay establish a logical interface (not shown) with the core network 106c. The logical interface between the WTRUs 102 a, 102 b, 102 c and thecore network 106 c may be defined as an R2 reference point, which may beused for authentication, authorization. IP host configurationmanagement, and/or mobility management.

The communication link between each of the base stations 180 a, 180 b,180 c may be defined as an R8 reference point that includes protocolsfor facilitating WTRU handovers and the transfer of data between basestations. The communication link between the base stations 180 a, 180 b,180 c and the ASN gateway 182 may be defined as an R6 reference point.The R6 reference point may include protocols for facilitating mobilitymanagement based on mobility events associated with each of the WTRUs102 a, 102 b, 102 c.

As shown in FIG. 1E, the RAN 104 c may be connected to the core network106 c. The communication link between the RAN 104 c and the core network106 c may defined as an R3 reference point that includes protocols forfacilitating data transfer and mobility management capabilities, forexample. The core network 106 c may include a mobile IP home agent(MIP-HA) 184, an authentication, authorization, accounting (AAA) server186, and a gateway 188. While each of the foregoing elements is depictedas part of the core network 106 c, it should be appreciated that any oneof these elements may be owned and/or operated by an entity other thanthe core network operator.

The MIP-HA 184 may be responsible for IP address management, and mayenable the WTRUs 102 a, 102 b, 102 c to roam between different ASNsand/or different core networks. The MIP-HA 184 may provide the WTRUs 102a, 102 b, 102 c with access to packet-switched networks, such as theInternet 110, to facilitate communications between the WTRUs 102 a, 102b, 102 c and IP-enabled devices. The AAA server 186 may be responsiblefor user authentication and for supporting user services. The gateway188 may facilitate interworking with other networks. For example, thegateway 188 may provide the WTRUs 102 a. 102 b, 102 c with access tocircuit-switched networks, such as the PSTN 108, to facilitatecommunications between the WTRUs 102 a, 102 b, 102 c and traditionallandline communications devices. In addition, the gateway 188 mayprovide the WTRUs 102 a, 102 b, 102 c with access to the networks 112,which may include other wired or wireless networks that are owned and/oroperated by other service providers.

Although not shown in FIG. 1E, it should be appreciated that the RAN 104c may be connected to other ASNs and the core network 106 c may beconnected to other core networks. The communication link between the RAN104 c the other ASNs may be defined as an R4 reference point, which mayinclude protocols for coordinating the mobility of the WTRUs 102 a, 102b, 102 c between the RAN 104 c and the other ASNs. The communicationlink between the core network 106 c and the other core networks may bedefined as an R5 reference point, which may include protocols forfacilitating interworking between home core networks and visited corenetworks.

A millimeter wave (mmW) communication system, for example an mmW meshnetwork that includes a plurality of nodes configured for mmWcommunication, may be integrated with a cellular communications system.For example, an mmW mesh network may be communicatively coupled to acellular communications system, such that one or more UEs (e.g., WTRUs)associated with the cellular communications system may leverage the mmWcommunications system, for example to send and/or receive data. Suchintegration may be implemented in accordance with a radio networkevolution (RNE) architecture model.

An implementation of integrating an mmW communications network with acellular communications network may include a cellular system overlaywith an mmW system underlay. The cellular system (or layer) may beconfigured to provide a control framework. The mmW system (or layer) maybe configured to provide one or more data pipes that may carry highthroughput data, for example. Higher layer control signaling (as wellphysical layer control) such as system information, paging, randomaccess channel (RACH) access, radio resource control (RRC), andnon-access stratum (NAS) signaling (e.g., signaling radio bearers)and/or multicast traffic, may be provided via the cellular layer, forexample. The mmW layer may be used as a default for transporting highthroughput traffic. The cellular overlay layer may be used to transportlow throughput and/or delay sensitive traffic. The mmW layer may havededicated PHY control signaling.

A UE may initially be connected to a cellular network before receivingand/or transmitting data on an mmW link. Low throughput and/or delaysensitive traffic may be carried by the cellular overlay layer, forexample when the network deems it more appropriate. One or more UEsconfigured with mmW capability may have UL and/or DL cellularcapabilities. The cellular layer may be used for mmW network control,connectivity and/or mobility management, for example. The cellular layermay carry L2 and/or L3 control messages, which may alleviate the mmWlayer from costs (e.g., resource costs) associated with these functions.

In an example system architecture, an mmW communications system may beconnected to a cellular communications system through a mesh backhaulsystem. The mmW network may include one or more base stations (e.g.,small scale base stations) that may be referred to as mmW base stations(mBs). The mBs may be within the coverage area of at least one networkdevice of the cellular communications system, for example an eNB. One ormore UEs that are capable of mmW communication, which may be referred toas mmW UE (mUEs), may be configured to operate using mmW and/or cellularlinks.

An integrated cellular network and mmW network architecture may includea logical and/or physical entity that may be referred to as an mmWgateway (mGW). An mGW may be configured so as to alleviate operationalcomplexity of one or more cellular base stations, for example withrespect to mmW control. An mGW node may be implemented as a separatephysical entity and/or may be collocated with a network device of thecellular network, for example an eNB or an S-GW. One or more mBs andeNBs may be physically collocated. Such mBs and eNBs may have separatelogical functions. An mGW may be configured to provide the network withadditional wired, fiber, and/or P2P PoP aside from the eNB, which mayprovide offload of mmW user traffic from the eNB, for example. In suchan example, the eNB may be responsible for providing control for mmWtraffic.

Procedures to convey information between the mGW and mUEs may beimplemented, for example in accordance with a dense deployment of mBsand/or high access link data rates. One or more mBs may be deployedclose to each other, for example in accordance with the relatively shortrange of mmW transmission and/or due to high path-loss (e.g.,penetration loss). The coverage area of an eNB may thus include a highnumber of mBs. It may be undesirable to establish direct physicalconnection between each mB and an associated mGW. Procedures may beimplemented to convey information between the mGW and one or moreassociated mUEs. Mesh mmW networking may be implemented, for example, asa candidate solution that may overcome the impracticality of fiberconnections, or as a substitute for long mmW links, and may beimplemented to encompass a relatively wide area coverage for an mmWcommunications system.

FIG. 2 depicts a block diagram of an example communications system 200that includes a cellular communications system and an associatedmillimeter wave (mmW) communications system. The communications system200 may include one or more MMEs and/or S-GWs 202, one or more eNBs 204,one or more mBs 206, and an mB management system (mB-MS) 208. Thecellular communications system may be, for example, an evolved UMTSterrestrial radio access network (E-UTRAN or Evolved UTRAN). The examplearchitecture of the communications system 200 illustrated in FIG. 2 maybe implemented, for example, in accordance with a radio networkevolution (RNE) system model. As shown, the communications system 200includes at least one eNB 204 that is collocated with at least one mB206, and may be referred to as a collocated deployment.

In a collocated deployment, the collocated mB 206 and the eNB 204 may beassumed to be physically located in a single chassis, such that the mB206 and the eNB 204 may communicate without the presence of a physicallink. The mB 206 and the eNB 204 may be physically the same device, butmay be logically defined as two separate functional entities. Forexample, the eNB 204 may be responsible for LTE RAN operation on thelicensed LTE spectrum, and the mB 206 may be responsible for operationin the mmW band, for instance using either LTE or non-LTE radio accesstechnology.

One or more of the mB 206 nodes may include respective logicalinterfaces to one or more MME/S-GWs 202 and/or one or more neighboringmB 206 nodes, for example via one or more Sx interfaces and/or mB-X2interfaces.

An Sx interface may support configuration of the mB 206 from an MME 202node. In an example implementation, the Sx interface may be split intoSx-MME and Sx-U, where Sx-MME may be an interface to an MME and Sx-U maybe an interface to an S-GW. In another example implementation, the SIinterface may be extended, for example with additional configurationmessages and/or parameters, so as to allow operation and/or managementof the mB 206 node.

One or more mB-X2 interfaces may be established, for example between mB206 nodes. An mB-X2 interface may be implemented, for example, as anoptional logical interface between mB 206 nodes. The mB-X2 interface maybe split into mB-X2-Control and an mB-X2-Data, for example to carrycontrol plane messaging and user plane messaging, respectively, betweenmB 206 nodes.

These logical interfaces may operate over any suitable physicalinterfacing options, and may be configured to operate in accordance withLayer 2 and/or Layer 3 messaging (e.g., IP and/or GTP).

Each mB 206 node may be managed by an associated mB-MS 208, which mayprovide an operations, administration, and maintenance (OAM) interface,for example to support startup, initial configuration and/or managementof one or more mB 206 nodes.

FIG. 3 depicts a block diagram of an example communications system 300that includes a cellular communications system and an associatedmillimeter wave (mmW) communications system. The communications system300 may include one or more MMEs and/or S-GWs 302, one or more eNBs 304,one or more mBs 306, and an mB management system (mB-MS) 308. Thecellular communications system may be, for example, an evolved UMTSterrestrial radio access network (E-UTRAN or Evolved UTRAN). The examplearchitecture of the communications system 300 illustrated in FIG. 3 maybe implemented, for example, in accordance with a radio networkevolution (RNE) system model. As shown, because there is not an eNB 304and an mB 306 that are collocated, the communications system 300 may bereferred to as a non-collocated deployment.

One or more of the mB 306 nodes may include respective logicalinterfaces to one or more MME/S-GWs 302 and/or one or more neighboringmB 306 nodes, for example via one or more Sx interfaces, one or moremB-X2 interfaces, one or more X2-C′ interfaces, and/or X2-U′ interfaces.One or more of these interfaces may be implemented in the E-UTRANsub-system, for example.

An Sx interface may support configuration of an mB 306 from an MME 302node. In an example implementation, an Sx interface may be split intoSx-MME and Sx-U, where Sx-MME may be an interface to an MME and Sx-U maybe an interface to an S-GW. In another example implementation, an Sx-Uinterface may be optional, for example where user-traffic for mBs 306 isrouted via the eNB 304 to which the mBs 306 are connected.

One or more mB-X2 interfaces may be established, for example between mB306 nodes. An mB-X2 interface may be implemented, for example, as anoptional logical interface between mB nodes 306. The mB-X2 interface maybe split into mB-X2-Control and an mB-X2-Data, for example to carrycontrol plane messaging and user plane messaging, respectively, betweenmB 306 nodes.

An X2-C′ interface may be a logical interface that may be establishedbetween an mB 306 and an associated eNB 304. An X2-C′ interface may beused, for example, for exchanging control signaling for management,and/or for co-ordination and/or configuration between the eNB 304 andthe mB 306 nodes. For example, X2-C′ messaging may carry configurationfor an initial setup. X2-C′ messaging may be initially sent over RRCsignaling, for example using a cellular connection, and may besubsequently transitioned to control messaging over a backhaul RAT.X2-C′ messaging may be carried over a cellular connection after initialsetup. This may allow for power savings over the backhaul interfaceproviding, for example by allowing the mmW backhaul link to be turnedoff completely when there is no traffic present (e.g., X2-U′).

An X2-U′ interface may be a logical interface that may be establishedbetween an mB 306 and an associated eNB 304. An X2-U′ interface may beused, for example, for data-plane messaging between the eNB 304 and themB 306 nodes. In an example implementation, an X2-U′ interface may carryRLC PDUs and/or MAC SDUs that may be sent to a UE through the mB 306node. The X2-U′ interface may be a per-UE, per-RB interface. IP packetsmay be carried over the X2-U′ interface.

These logical interfaces may operate over any suitable physicalinterfacing options, and may be configured to operate in accordance withLayer 2 and/or Layer 3 messaging (e.g., IP and/or GTP).

Each mB 306 node may be managed by an associated mB-MS 308, which mayprovide an operations, administration, and maintenance (OAM) interface,for example to support startup, initial configuration and/or managementof one or more mB 306 nodes. A direct OAM interface may be establishedbetween the mBs 306 and the mB-MS 308. An mB 306 may have a connectionto an IP network. For example, at startup the mB 306 node may beconnected to the IP network and may maintain an independent IP address.This may allow for a direct interface to the mB-MS 308.

FIG. 4 depicts a block diagram of an example communications system 400that includes a cellular communications system and an associatedmillimeter wave (mmW) communications system. The communications system400 may include one or more MMEs and/or S-GWs 402, one or more eNBs 404,one or more mBs 406, and an mB management system (mB-MS) 408. Thecellular communications system may be, for example, an evolved UMTSterrestrial radio access network (E-UTRAN or Evolved UTRAN). The examplearchitecture of the communications system 400 illustrated in FIG. 4 maybe implemented, for example, in accordance with a radio networkevolution (RNE) system model. As shown, because there is not an eNB 404and an mB 406 that are collocated, the communications system 400 may bereferred to as a non-collocated deployment.

One or more of the mB 406 nodes may include respective logicalinterfaces to one or more MME/S-GWs 402 and/or one or more neighboringmB 406 nodes, for example via one or more Sx interfaces, one or moremB-X2 interfaces, one or more X2-C′ interfaces, and/or X2-U′ interfaces.One or more of these interfaces may be implemented in the E-UTRANsub-system, for example.

An Sx interface may support configuration of an mB 406 from an MME 402node. In an example implementation, an Sx interface may be split intoSx-MME and Sx-U, where Sx-MME may be an interface to an MME and Sx-U maybe an interface to an S-GW. In another example implementation, an Sx-Uinterface may be optional, for example where user-traffic for mBs 406 isrouted via the eNB 404 to which the mBs 406 are connected.

One or more mB-X2 interfaces may be established, for example between mB406 nodes. An mB-X2 interface may be implemented, for example, as anoptional logical interface between mB nodes 406. The mB-X2 interface maybe split into mB-X2-Control and an mB-X2-Data, for example to carrycontrol plane messaging and user plane messaging, respectively, betweenmB 406 nodes.

An X2-C′ interface may be a logical interface that may be establishedbetween an mB 406 and an associated eNB 404. An X2-C′ interface may beused, for example, for exchanging control signaling for management,and/or for co-ordination and/or configuration between the eNB 404 andthe mB 406 nodes. For example, X2-C′ messaging may carry configurationfor an initial setup. X2-C′ messaging may be initially sent over RRCsignaling, for example using a cellular connection, and may besubsequently transitioned to control messaging over a backhaul RAT.X2-C′ messaging may be carried over a cellular connection after initialsetup. This may allow for power savings over the backhaul interfaceproviding, for example by allowing the mmW backhaul link to be turnedoff completely when there is no traffic present (e.g., X2-U′).

An X2-U′ interface may be a logical interface that may be establishedbetween an mB 406 and an associated eNB 404. An X2-U′ interface may beused, for example, for data-plane messaging between the eNB 404 and themB 406 nodes. In an example implementation, an X2-U′ interface may carryRLC PDUs and/or MAC SDUs that may be sent to a UE through the mB 406node. The X2-U′ interface may be a per-UE, per-RB interface. IP packetsmay be carried over the X2-U′ interface.

These logical interfaces may operate over any suitable physicalinterfacing options, and may be configured to operate in accordance withLayer 2 and/or Layer 3 messaging (e.g., IP and/or GTP).

Each mB 406 node may be managed by an associated mB-MS 408, which mayprovide an operations, administration, and maintenance (OAM) interface,for example to support startup, initial configuration and/or managementof one or more mB 406 nodes. A direct OAM interface may be establishedbetween the mBs 406 and the mB-MS 408. An mB 406 may have a connectionto an IP network. For example, at startup the mB 406 node may beconnected to the IP network and may maintain an independent IP address.This may allow for a direct interface to the mB-MS 408.

Each mB 406 node may be managed by an associated mB-MS 408, which mayprovide an operations, administration, and maintenance (OAM) interface,for example to support startup, initial configuration and/or managementof one or more mB 406 nodes. As shown, the mBs do not have respectivedirect connections to an IP network, but may establish respectivecellular interfaces with an associated eNB 304, for example to obtaininitial configuration from the eNB 404. The eNB 404 may establish aconnection to the mB-MS 408, and may provide configuration to the mB 406nodes, for example when the mB 406 nodes attach to the cellular networkusing respective cellular connections. The mB 406 nodes may directly orindirectly (e.g., via the eNB 406) connect to one or more other E-UTRANcomponents.

FIG. 5 depicts a block diagram of an example communications system 500that includes a cellular communications system and an associatedmillimeter wave (mmW) communications system. The communications system500 may include one or more MMEs and/or S-GWs 502, one or more eNBs 504,one or more mBs 506, and an mB GW 508. The cellular communicationssystem may be, for example, an evolved UMTS terrestrial radio accessnetwork (E-UTRAN or Evolved UTRAN). The example architecture of thecommunications system 500 illustrated in FIG. 5 may be implemented, forexample, in accordance with a radio network evolution (RNE) systemmodel. As shown, the communications system 500 includes at least one eNB504 that is collocated with at least one mB 506, and may be referred toas a collocated deployment.

In a collocated deployment, the collocated mB 506 and the eNB 504 may beassumed to be physically located in a single chassis, such that the mB506 and the eNB 504 may communicate without the presence of a physicallink. The mB 506 and the cNB 504 may be physically the same device, butmay be logically defined as two separate functional entities. Forexample, the eNB 504 may be responsible for LTE RAN operation on thelicensed LTE spectrum, and the mB 506 may be responsible for operationin the mmW band, for instance using either LTE or non-LTE radio accesstechnology.

The presence of the mB GW 508 may allow the one or more Sx interfacesbetween the mBs 506 and an evolved packet core (EPC) to support a largenumber of mBs 506, for example in a scalable manner. The mB GW 508 maybe configured to operate as a concentrator for the C-Plane, for examplefor the Sx-MME interface. One or more Sx-U interfaces from the mBs 506may be terminated at the mB GW 508. A direct logical U-Plane connectionestablished between an associated cNB 504 and an S-GW 502 may be used.The mB GW 508 may operate to perform the functions of an mB-MS, forexample to support startup, initial configuration and/or management ofone or more mB 506 nodes.

FIG. 6 depicts a block diagram of an example communications system 600that includes a cellular communications system and an associatedmillimeter wave (mmW) communications system. The communications system600 may include one or more MMEs and/or S-GWs 602, one or more eNBs 604,one or more mBs 606, and an mB GW 608. The cellular communicationssystem may be, for example, an evolved UMTS terrestrial radio accessnetwork (E-UTRAN or Evolved UTRAN). The example architecture of thecommunications system 600 illustrated in FIG. 6 may be implemented, forexample, in accordance with a radio network evolution (RNE) systemmodel. As shown, because there is not an eNB 604 and an mB 606 that arecollocated, the communications system 600 may be referred to as anon-collocated deployment.

The presence of the mB GW 608 may allow the one or more Sx interfacesbetween the mBs 606 and an evolved packet core (EPC) to support a largenumber of mBs 606, for example in a scalable manner. The mB GW 608 maybe configured to operate as a concentrator for the C-Plane, for examplefor the Sx-MME interface. One or more Sx-U interfaces from the mBs 606may be terminated at the mB GW 608. A direct logical U-Plane connectionestablished between an associated eNB 604 and an S-GW 602 may be used.The mB GW 608 may operate to perform the functions of an mB-MS, forexample to support startup, initial configuration and/or management ofone or more mB 606 nodes.

Communications between an mUE and an associated eNB (e.g., 204, 304,404, 504, or 604) and/or an associated mGW (e.g., 508 or 608) may beachieved through one or more mBs that are interconnected and may form anmmW mesh network. Mesh backhaul may extend from an eNB and may requiremore than one hop. In an mmW mesh network, a large number of mBs may bewithin range of one or more other mBs, which may provide many possibleroutes. In such an mmW mesh network, each mB may be able to reach one ormore neighboring mBs using wireless mmW backhaul links, for example whena wired backhaul link is not available.

Backhaul links (e.g., wired or wireless) between different mBs (e.g., mBto mB), and between one or more mBs and other network devices (e.g., mGWnodes) may form a multi-hop mesh network, for example such that longbackhaul links may not be required. This may reduce capital expenditure.Backhaul reliability may be achieved via multiple paths. Backhaul linksbetween an mGW and one or more mBs may be significantly different fromthe backhaul links between different mBs (e.g., mB to mB), for examplein terms of physical medium used, such as mmW wireless links,fiber-optic links, or the like.

Link adaptation techniques may be employed in the backhaul (e.g., HARQand fast AMC), such that each link may operate nearer to a correspondingchannel capacity. This may support greater spectral efficiency. Forexample, each node in a routing path of a packet, or part of a packet ora bundled packet, may use an estimated channel quality to select a mostappropriate MCS for a desired TP and a max number of HARQre-transmissions.

AMC may be slow and conservative, and HARQ may be omitted, for exampleto support lower latency and/or lower overhead. For example, a minimumexpected link quality in a full routed path of a packet may be used todefine an MCS so that there is a high probability of delivery withoutone or more nodes (e.g., each node) in the path re-encoding the packetto better match the link capacity of the links used to deliver thepacket from mB to mB.

In an example, one or more mesh nodes may employ amplify-and-forwardtransmission, such that they amplify a received analog signal andforward the amplified signal to a neighbor mesh node in the route. Adetermination of an amplification factor may be done locally (e.g., ateach node), and may depend on one hop backward and forward channels.

In another example, one or more mesh nodes may employ decode-and-forwardtransmission, such that each node decodes the packet and forwards it toa next hop in the route. During a decoding and re-encoding process, oneor more errors in the packet (e.g., errors created due to noiseaccumulation during AF transmission) may be corrected. The MCS of thepacket may not be affected, such that rebundling may not be required,and such that low-latency transmission may be achieved.

In another example, an eNB may determine the MCS of the packet and mayinform one or more nodes that pass the packet through the mesh network.This may be valid for both amplify-and-forward and decode-and-forwardtransmission. The eNB may obtain channel conditions, buffer conditions,etc. from one or more nodes in the network, and may calculate a bestpossible MCS. This information may be conveyed by one or more mesh nodesto the eNB, for example through one or more cellular layer controlmessages such as PUCCH. The MCS of the packet may be conveyed to thenodes via PDCCH.

A backhaul link and access link may use the same frequency resources,and may enjoy benefits from trunking efficiency and/or directionaltransmission. Signal transmission from an mGW to an mUE may involveroute determination between the mGW and the mUE, including one or moremBs in between, such that joint RRM of backhaul and access links may beimplemented. In other words, in a scenario where access and backhaul maysimultaneously contend for at least some of the mmW spectrum, routingand/or scheduling may be considered jointly.

If separate bands are available in an mmW band, for example if the 60GHz unlicensed band is channelized into several 2 GHz channels, one ormore orthogonal bands may be utilized both for access links and backhaullinks. Utilizing orthogonal bands between access links and backhaullinks may separate short time scale RRM aspects of these links, but mayslow channel assignments, for example if backhaul and/or access are yetto be negotiated. Per channel load information may be signaled to anmB-MS (e.g., over cellular radio resources), such that per link channelsmay be assigned to access or to backhaul.

A channelized band (e.g., 60 GHz) may designate one or more channels inone or more links as backhaul or as access. These designations may bechanged, for example on a frequent basis. For example, one or more mBsmay sense an environment for availability of channels for access and/orbackhaul, and may make designations autonomously. A channelized band(e.g., 60 GHz) may designate one or more channels in one or more linksas joint backhaul and access.

Separate bands (e.g., 60 GHz and E-band) may be used for access andbackhaul, respectively. This may separate access and backhaul radiointeractions. The separate bands may be used for special links, forexample links expected to have particularly heavy loads. For example,mGW to and/or from mB links may use E-band, while mB to and/or from mBlinks may use 60 GHz.

Links between mBs and an mGW may be of various forms, for example mmW(e.g., 60 GHz, E Band), fiber, copper, etc., such that a heterogeneousnetwork is defined. The same mmW spectrum may be used for both backhauland access links, for example due to the high directionality of mmWbeams. In such an example, a joint backhaul and access link RRM for themmW system may be implemented. The presence of a LOS path on one or morebackhaul links may be beneficial. The support of limited NLOS may bedesirable. This may be accomplished by steering beams around lossyobstructions, for example people. One or more backhaul links may providerespective attributes and/or capabilities to a backhaul routingprotocol. Such attributes and/or capabilities may include, for example,an average link capacity, an average latency, an average QoS capability,an average SINR, an average availability, a reliability, etc., which maybe denoted as Cij. A mesh backhaul routing protocol (MBRP) may be awareof corresponding states of one or more backhaul links in a system, alongwith their respective attributes.

Millimeter wave backhaul links may not be static, in contrast with thebackhaul links of typical cellular systems. Mesh backhaul (mmW meshbackhaul) may provide one or more alternative routes. If a need for anmmW backhaul link is established dynamically, an mmW backhaul link maybe setup on the fly. This may provide an ability to use resources whereand when required, and may allow for efficient sharing of resources, forexample between access and backhaul. This may allow for more aggressiveDRX and/or power save schemes that may not be feasible in typicalbackhaul networks.

In an example implementation, it may be possible to deploy mBs (e.g.,deployed on lamp-posts) configured to operate above the ground (e.g.,approximately 3 m to 6 m above the ground). Such mBs may encountercomparatively few obstacles from mB to mB, even when deployed belowrooftop. The mBs may communicate with each other, at least via mmWlayer, and may form a mesh network. One or more mBs (e.g., in closeproximity to an associated eNB or mGW) may forward traffic to thesenodes. Access traffic from multiple mBs may ultimately be funneled toone or more backhaul links. The backhaul links may enjoy better overallcapacity, for example due to better and/or higher placement, the use oflarger antennas at one or both ends of a link, and/or less loss that maybe due to beam tracking.

A cellular communications system may have a degree of control over anmmW network. The degree of control exerted by the cellular layer may beconfigured at various levels. The cellular layer may not haveinformation about instantaneous mB to mB channel gains, interference,congestion, etc.; but may have statistical knowledge about them. Forexample, semi-static and/or slowly changing measurements may be reportedto the network regarding the mmW layer. This information may be conveyedby one or more mBs to an associated eNB through periodic signals in thecellular layer, for example.

Utilizing the above-discussed information obtained from the mmW system,the cellular layer may influence one or more routing protocol decisionswith the long-term routing statistics. By combining long-term networkconditions obtained from the cellular layer (that might be in the formof a suggested route to be followed and/or one or more route segments toavoid) along with the instantaneous channel, traffic, etc. conditions athand, the mBs may decide a next step (e.g., a next mB) in the route. Oneor more mBs may be configured to periodically report average linkqualities, availabilities, and/or interference measures to one or moreneighboring mBs, and/or access link loads, to the cellular layer. Thecellular layer may provide suggested routes to the mB mesh network, forexample based on such information. The mB mesh network may use theseroutes to bias one or more short term routing decisions towards thoseprovided by the cellular layer. The suggested routes may be on a perUE-traffic class basis, for example.

The mBs of an mmW mesh network Node (mB) may be configured with variouscapabilities (e.g., the same or different capabilities on a per mBbasis). For example, one or more mBs may be configured to operate indecode-and-forward mode with buffering capabilities. One or more mBs maybe configured with joint reception and transmission capability byforming multiple simultaneous beams. For example, each mB may beconfigured to support multiple Rx beams or multiple Tx beams at the sameinstant (e.g., substantially concurrently). Each mB may be configured toemploy a degree of spatial separation via beam forming, for examplethrough multiple antennas per mB or through supporting multiple beamsfrom an antenna array.

One or more mB may be configured with multiple Rx beams that may receivedifferent data from different sources. The different sources may be amixture of access and/or backhaul link traffic. One or more mB may beconfigured with multiple Tx beams that may transmit different data todifferent receivers. The different receivers may be a mixture of accessand/or backhaul link traffic. A routing algorithm may be implemented tobe compatible with this feature.

An mB may be configured with multiple antenna arrays, switched arrays ofhorns, etc. The mB may have physically separate arrays for Tx and Rx, orthe arrays may be shared. If an mB is configured with separate arraysfor Tx and Rx, the mB may be configured not to perform Tx and Rxoperations at the same time in the same band. Routing decisions may takethis into account, such that routing may not assume that an mB may Txand Rx at the same time in the same band. One or more mBs may haverecent channel state information (CSI) pertaining to the links of one ormore neighboring mBs (e.g., first hop mBs). One or more mBs may employAMC and/or HARQ with one or more other mBs, for example an mB to whichone or more packets may be routed in a next hop.

An mB may be configured to screen one or more channels periodically, forexample to identify mB nodes added to the system. Periodicity andconfiguration procedures of the channel screening may be implemented.One or more mBs may be configured to perform packet re-segmentationand/or bundling. One or more routing schemes and/or RRM may be optimizedaccordingly. In this way, one or more data flows (e.g., for differentUEs) may be aggregated in one or more backhaul links. The one or moredata flows may be aggregated differently as the flows traverse thenetwork.

An mB may be deployed in a collocated or a non-collocated location withrespect to an associated eNB. When an mB is installed, the mB device maybe packaged with an mB identification (mB ID). The mB ID may be used toregister and/or authenticate the mB in the network, for example when themB is powered on. When an mB is powered up on a network, information maybe provided to an operator of the network. This information may beparameters including a location of the mB device installation, a list ofmB subscribers (e.g., registration data), access control restrictionsthat mB device is to be operated in accordance with, etc. Access controlinformation may be in the form of a subscription validation list, asubscriber's authentication preferences, policy parameters, and so on.The radio parameters of the mB may be set to a default configurationwhen the mB is powered on.

After being powered up, the mB may interface with an associated mB-MS(e.g., during an mB setup procedure). The mB may obtain configurationparameters (e.g., from the mB-MS) that may include one or more of:frequencies for DL and/or UL; a scrambling code list; a radio channelbandwidth that may be provided during a booting procedure by an operatorover a backhaul link; a geographic location, routing and/or service areacode information; a list of neighboring mBs; a physical cell ID; and oneor more RF parameters (e.g., pilot and maximum data power, and thelike).

An mB may be configured to calculate some of these configurationparameters, for example using information on the macro-cell layer thatmay be provided by the operator, and/or from information on the mB layerprovided by the installer and/or user of the mB (e.g., registrationdata). Depending on the capabilities of the mB, this configurationinformation may be provided to the mB either directly through connectionto the mB-MS, or may be provided to the mB via an associated eNB.

An mB may be installed in a collocated deployment with an associated eNBdevice. When a collocated mB is powered up, or when an mB starts up witha connection to an IP network, the mB may connect to an associatedmB-MS. Through communication with the mB-MS, the mB may be authenticatedand/or registered into the system as an operative device (e.g., over anOAM interface), may obtain configuration parameters, and the like. FIG.7 illustrates an example setup procedure 700 for an mB that iscollocated with an associated eNB device.

An mB may be installed in a non-collocated deployment, for example asdescribed herein. Upon being powered on, a non-collocated mB may beconfigured to interface with an associated mB-MS. In an example, the mBmay have a direct interface to the mB-MS. The mB may have a connectionto an IP network, such that the mB node may be connected to the IPnetwork at startup, and may maintain an independent IP address. This mayallow the mB to establish a direct interface to the mB-MS. In anotherexample, the mB may interface with the mB-MS via an associated eNB. ThemB may not have a direct connection to an IP network, but may have acellular interface that it may use, for example, to obtain initialconfiguration from the eNB. The eNB may connect to the mB-MS, and mayprovide configuration information to the mB node, for example when themB attaches to the network using the cellular connection. An mB node maydirectly or indirectly (e.g., through the eNB) connect to one or moreother E-UTRAN components.

An mB may be configured to perform eNB discovery, for example when themB is powered on (e.g., during an mB setup procedure). In an example,the mB may have cellular capabilities and may perform cell selection todiscover a suitable eNB, for example based on one or more of eNBcapabilities, signal strength, an operator white list, a list of PLMNssupported, etc. The suitability of an eNB may be determined, forexample, by reading eNB capabilities sent on the system information thatmay include one or more of back-haul RATs supported, back-haulcapabilities, a capacity, a load, a QoS supported, and the like. Inanother example, the mB may discover the eNB by using backhaul RATdiscovery procedures, for example one or more beacons on 802.11ad witheNB indication.

FIG. 8 illustrates an example setup procedure 800 for an mB thatinstalled in accordance with a non-collocated deployment. The mB mayhave a direct interface to an associated mB-MS. The mB may perform mBstart-up and initial configuration procedures using a direct connectionto an IP network, for example. The mB may obtain mB-MS configurationinformation directly. The configuration information may include one ormore of a candidate list of eNBs that the mB may choose from based onsignal strength, eNB back-haul RAT options, eNB back-haul RATcapabilities, and the like.

FIG. 9 illustrates an example setup procedure 900 for an mB thatinstalled in accordance with a non-collocated deployment. The mB mayhave an indirect interface to an associated mB-MS (e.g., via anassociated eNB). The mB may perform mB start-up and initialconfiguration procedures using cellular discovery of eNB, for example.The mB may select a suitable eNB, for example based on suitabilitycriteria. Such suitability criteria may include one or more of receivedsignal strength, eNB back-haul RAT options, eNB back-haul RATcapabilities, and the like. The eNB may advertise its capabilities usingbroadcast messaging, for example system information in a cellularsystem, or beacons in an 802.11ad system. The eNB may advertise itscapability to operate as a back-haul eNB, for example such that an mBmay recognize the eNB as a candidate eNB. The mB may obtain mB-MSconfiguration information indirectly. For example, the mB-MS may sendconfiguration to the eNB, and the eNB may configure the mB based on thisinformation, for example using RRC signaling. The mmW transmissioncapability of the mB, for example including transmission power, antennagain. Tx range-capacity data, etc., may be exchanged with the eNB. TheeNB may use this information in a recommendation process of mB neighborcandidates to one or more other mBs.

After the initial start-up procedures for the mBs of an mB network arecarried out, a capacity of the mB backhaul system may be determined. Therespective deployment scenarios of the mBs (e.g., co-located andnon-collocated mB and eNB) may provide different mesh connectivityoptions among the mBs comprising a backhaul network. The backhaulcapacity information (e.g., respective capacity of each mB to mB link)may be integral to the backhaul-access link RRM and/or to correspondingrouting protocols.

After the respective initial start-up procedures of the mBs in the meshbackhaul system are completed, the mB to mB link capacity may bedetermined, for example by measuring respective signal powers and/orinterference powers between the mBs for possible Tx and/or Rx beamcombinations. This process may be performed with aid from the cellularsystem. This information may be used to initiate mB to mB linkestablishment and/or may be input into a routing algorithm. FIG. 10depicts a block diagram of an example mB mesh backhaul system 1000, withinitial link measurement.

In an example procedure of admitting a candidate mB into an mB mesh,each candidate mB may obtain an initial mesh neighbor candidate set. Anassociated eNB may be non-collocated with respect to an associatedmB-MS. In an example of obtaining this set, the eNB may inform thecandidate mB regarding the locations and/or respective distances of oneor more the neighbor mBs (e.g., mB IDs and corresponding geographiclocations) that are available and may be willing to establishconnections in order to form the mesh. Respective directions oflocations of one or more neighbor mB nodes may be incorporated into thelocation information.

In another example, a candidate mB may attempt to decode respectivesignals transmitted by one or more neighbor mBs (e.g., beacons) in orderto obtain basic information (e.g., location, mB ID, etc.). The candidatemB may perform this, for example, by sweeping its receive beam and/or byemploying omni-directional reception. Upon identifying one or morepotential neighbor mBs, the candidate mB may inform the eNB about thesenodes (e.g., via a candidate neighbor list). The eNB, based oncapability information received from one or more other mBs, may sendacknowledgment information to the mB. The acknowledgement informationmay indicate whether the mB should consider the mBs in the list aspotential neighbors or not. The capabilities of one or more mBs in theset, such as maximum transmission capacity, etc., may not be sufficientfor the mBs to be considered as candidate mesh neighbors.

In another example, the mB may attempt to decode the respective beaconsof one or more neighbor mBs, for example by utilizing locationinformation obtained by the eNB. Depending on the neighbor mB locationinformation, the mB may narrow and/or refine its receive beams in thisdirection and/or in one or more other directions (e.g., adjacentdirections).

The admission of a candidate mB into an mB mesh network may beassociated with the establishment of an average signal strength (e.g.,propagation losses plus antenna gains) of the candidate mB relative toone or more (e.g., each) of the neighboring mBs, when the neighboringmBs have their beams pointed in respective directions that would be usedto communicate with each other.

For each such link, interference caused by transmission to and/or fromthe candidate mB may cause interference to one or more other neighbormBs. This interference may depend, for example, on the propagationchannel and on the respective directions that one or more neighborantennas are directed. For each such transmission, there may beKT=K₁+K₂+ . . . +K_(M) interference measurements, where K_(M) may be thenumber of possible pointing directions for mB M. For analysis of abackhaul network, the pointing direction of the antennas of one or moreneighbor mBs may be towards one of a limited number of other mBs. Incontrast, for an access link analysis, the direction of the access linkmay be drawn from a much larger set of other mBs.

To illustrate, an example mB signal and/or interference measurementprocedure for a mesh mB backhaul system is described. A deploymentscenario of non-collocated mBs with cellular connection capabilities, asdescribed herein, is considered. An initial procedure for an mB to beadmitted to the mesh network is considered.

A candidate mB (e.g., a device that desires to become an mB) may firstconnect to an associated cellular network (e.g., in a manner similar toa UE) and may request to join the mmW network. The candidate mB may readSIB information, for example to determine whether the eNB supports anmmW layer and/or layers, and may extract minimum requirements of an mmWmesh layer. Such minimum requirements may include, for example, one ormore mmW bands, a minimum data rate, a Tx power, an antenna gain, anumber of simultaneous Tx, a number of simultaneous Rx, and the like.

The candidate mB may check these requirements against its owncapabilities. If satisfied that the requirements will be met, thecandidate mB may make a request (e.g., via RRC signaling) to join themesh network. The candidate mB may send its mB-ID. The request mayinclude other information, for example location coordinates, that mayhelp an associated eNB decide whether the approximate location of thecandidate mB may be beneficial.

The eNB (e.g., an mB-MS) may deny the request, may request mB capabilityclass information, or may initiate HO to another eNB. An HO may be due,for example, to eNB capabilities, PLMN exclusion, etc. The eNB mayinform an associated mB-MS regarding the HO decision. The eNB may conveyinformation regarding one or more preferred eNBs obtained from thecandidate mB to the mB-MS. The candidate mB may select the preferredeNBs based on one or more criteria, for example received signalstrength, support of mmW, etc.

The candidate mB may send the eNB (e.g., the mB-MS) the mB capabilitiesinformation and/or the mB-ID of the mB, for example if the mB-MSresponds with the request.

The eNB (e.g., the mB-MS) may authenticate the mB-ID of the candidatemB. One or more UE authentication procedures (e.g., AS and NAS) may beapplied for authentication, for example.

The candidate mB may obtain a candidate mesh mB neighbor list, forexample in accordance with an initial mesh neighbor candidate set asdescribed herein.

The eNB may deny the request or may proceed to test the candidate mB forconformance. The eNB may initiate beam acquisition procedures, forexample as if the candidate mB was a UE requesting mmW resources, withone or more mBs in the mmW network (e.g., including the eNB if it isco-located with an mB). Before initiating the beam acquisitionprocedure, the eNB may inform one or more mBs in the candidate setregarding the intent of the candidate mB to perform beam acquisitionprocedures with the one or more mBs. The information conveyed may beused in a beam refinement procedure between one or more of the mBs. Theinformation elements may include, for example, a beam acquisition starttime, a duration of beam refinement, a number of beams to be tested,etc.

If initial beam acquisition is successful, one or more data rate and/orlink stability measurements of the link may be made. An enhanced mmWneighbor list may be created. The candidate mB may enter a mode offrequent updates to the neighbor list. In addition to link qualities,historical traffic patterns and/or historical backhaul load beyond theneighbor list may influence the preferred location of the candidate mBand may be included in the enhanced neighbor list.

Deployment aid information may be sent to the candidate mB. Thedeployment aid information may be in the form of suggested newapproximate coordinates of the candidate mB, such that one or more othermBs may be added to the neighbor list, for example. The deployment aidinformation may be in the form of feedback of signal strength over smallcandidate mB position changes, for example to help avoid shadowing ofsmall fixed objects like lampposts.

The candidate mB and the mB-MS may negotiate the physical position ofthe candidate mB, for example by frequent updates of the deployment aidinformation. In positions and/or orientations acceptable to the network,the candidate mB may request an End of Position Negotiation.

After a physical position and/or orientation of the candidate mB isfixed (e.g., after an ACK of an End of Position Negotiation request),the mB-MS may coordinate a measurement campaign between the candidate mBand one or more mBs in the enhanced mmW neighbor list, as describedherein. During this process, a beam refinement stage may be enteredbetween each mB in the list and the candidate mB, in which the beamdirections may be further refined, for example to maximize signalstrength in the desired Rx.

One or more quiet periods may be forced (e.g., sparsely) into one ormore nearby mBs and/or mUEs, so that one or more better signal strengthmeasurements (and variability) for all the mB to mB links, on a per beamdirection basis, may be made, for example as described herein. The eNBmay coordinate the scheduling of each mB it is attached to, in order toschedule the signal strength measurement campaign. For example, the eNBmay schedule each neighbor mB pair using a TDMA fashion, so that they donot interfere during the measurement campaign. If there are any, mBpairs that are physically far apart may be scheduled simultaneously bythe eNB, in order to accelerate the process.

For each mB in the list and the candidate mB, specific Rx and/or Txbeams used may also be scheduled so specific interference measurementsmay be made. An associated eNB may determine an interference measurementschedule, and may provide this schedule to one or more mBs. One or moremBs may, based upon the interference management schedule, determinewhere (e.g., with respect to direction) and/or when to point theirrespective Tx and/or Rx beams, for example during an interferencemeasurement campaign.

For example, a candidate mB may point to an mB_5, and mB_5 may point tothe candidate mB (for a signal measure), and one or more other mBs inthe list may point Rx beams to specified mB neighbors to get measures ofinterference when they are receiving from those specified beamdirections. Measurements may be made in both directions (e.g., candidatemB to mB and mB to candidate mB). The measurements of the desired signaland/or the neighbor interference strengths may be sent back to themB-MS, and a suitable list of mB mesh links may be selected and/or maybe signaled to the candidate mB and/or one or more other affected mBs.

Recommended power levels may be incorporated. One or more short linksmay be able to make use of a very high SINR, but may cause a near farproblem with one or more other links. For example, the eNB may order oneor more mBs to adjust their respective radiated transmit powers, forexample by changing the Tx power and/or antenna gain at particularbeams, in order to reduce interference at one or more neighbors. Thepower adjustment of the beams may be iterative, such that the radiatedbeam power may be repeatedly changed as a measurement campaign at aparticular mBs is carried out.

A beam shape refinement operation (e.g., for one or more beams used inthe list of mesh links) may be performed. During beam refinement, therespective beam shapes of the candidate mB and one or more affected mBsmay place nulls, or may otherwise alter the beam shape, in order tominimize interferences. Example interference may include interferencescaused by transmissions of the candidate mB and the one or more affectedmBs to the respective Rx beams of other mBs. One or more Tx beams may bemodified to reduce interference, for example for one or more worstcases. Example interference may include interference seen bytransmissions from one or more mBs on the respective Rx beams of othermBs. One or more Rx beams may be modified to reduce interference, forexample for one or more worst cases.

Once the affected mBs and the candidate mB acknowledge the updated meshlink list, the candidate mB state may be made ‘mB’, for example by theeNB. One or more other mBs of the mB mesh network may be notified of thecandidate mB joining the mmW mesh network. Backhaul traffic may berouted through the accepted candidate mB, and the cellular system mayrequest that the accepted candidate mB service access link traffic.

An example mB direction discovery and interference measurement proceduremay include time division, a discovery phase, and an output. During timedivision, a representative network composed of mBs, for example asdepicted in FIG. 10, may be considered. The mBs (e.g., mB₁ . . . mB₉)may be configured to learn possible beam directions between each otherand/or may be configured to measure interference levels between eachother.

Each mB may be allocated one of a number of predetermined(non-overlapping) time slots for signal measurement. In order to shortenan overall link establishment period in the system, one or more mBs withsufficient spatial separation may simultaneously apply measurementprocedures. The cellular layer may determine which mBs may transmitbeacons (e.g., beams) that may be used for signal measurement, and mayprovide synchronization (e.g., start and end times of the linkacquisition periods). One or more techniques, such as spreading and/orFDM, may be employed to further enable separation of mB signals.

During the discovery phase, one or more beacon transmissions and/orsignal measurements may be performed. A scheduled mB may perform beamsteering. For example, the scheduled mB may transmit one or more beaconsin a predetermined direction dir for each antenna array, wheredir=(α,θ,φ) with α,θ,φ ∈[−π/2,π/2] at a given time. One or morereceiving mBs in the enhanced neighbor mB list may listen to the beacontransmissions by the scheduled mB. A fixed step-size may be assumed foreach angular transmission. Each array may be denoted as k, k=1, 2, . . .N. To illustrate: t=[0,t1]: mB7 beam steering, {mB4,mB5,mB8} listen andmeasure signal and interference strength (assuming 2nd tier mBs andbeyond do not receive); and t=[t1,t2]: mB8 beam steering,{mB7,mB4,mB5,mB6,mB9} listen and measure signal and interferencestrength.

For a scheduled mB, for example during a time duration [tm,tn], thefollowing may be followed.

k=1,for array=k

One or more neighboring mBs may listen to the transmitting mB. For aselect angular transmission, dir, for array k of the transmitting mB,one or more receiving mBs may measure the received signal by all antennaarrays (e.g., wide beam reception). For example, separate measurementsmay be made for each possible Rx beam, or the array may be configured toapproximate a near-omni for a single measurement, or for a subset ofmeasurements.

Each mB may inform the cellular layer about the received signal powersat each antenna array at the transmission direction dir (and possiblyfor each possible Rx beam). This may be repeated for all transmissiondirections. Alternatively, a best pointing direction for each mB mayfirst be identified and information signaled to the network may belimited to those relevant beams.

When the transmitting mB completes the beacon transmission at all dir(e.g., completes beam sweeping), the cellular layer may order thereceived signals for all mBs and their antenna arrays out of allpossible antenna array and transmission direction combinations, forexample from higher to lower values. As an example, mB8 may beidentified as having a highest received power from its receiving antennaarray=A (assuming near-omni reception), and for the transmissiondirection=D. An ordered vector PmBRK may be assumed, where each entrygives a received power strength at a particular mB, its antenna array k,and the transmission direction, dir. This vector may be considered as adatabase which contains the received powers from all possibletransmission beam (of a particular mB), receiving mB and its array, andtransmit beam direction combinations. Alternatively, in a case ofseparate Rx beam measurement at each array, the database may be extendedto include this information.

This database may be refined, for example by employing a beam refinementprocedure between the candidate mBs that is saved at the cellulardatabase as an ultimate link SNR value. One or more interferencemeasurement at the neighbor mBs may be carried out, and may be saved atthe database.

ind=1;

for ind<length(PmBRK)

For example, choose (Receiving mB, array, dirf=PmBRK (ind). PmBRK may bean ordered vector.

The cellular layer may schedule the transmitting mB and the receiving mBand its particular array, to employ a beam refinement procedure.

After the beam refinement procedure is completed between thetransmitting and the selected receiving mB (e.g., after transmit beamrefinement and receive beam selection and refinement), the receiving mBmay measure the received signal quality, and may inform the cellularlayer. This information may be stored in the cellular database and maybe denoted as SNR_(mBr) ^(mBtk). This may be read as SNR at receivedmBr, transmitted by mBt from array k.

One or more other mBs may measure the received signals upon the pairedmBs, to complete the beam refinement procedure. If the receiving mBalready knows the particular Rx beams it is allocating for thecommunication with the other mBs, then the measurement may be performedat these particular beams. If not, the measurement may be performed atall arrays and this information may be stored in the cellular database.Each mB i may provide an interference vector denoted by INR_(mBi)^(mBtk)=[INR_(mBi1) ^(mBtk), INR_(mBi2) ^(mBtk), . . . , INR_(mBiN)^(MBtk)]^(T) that denotes the interference power level at each antennaarray. If the Rx beams are allocated to other mB transmissions, theentry of this vector may contain the INR value measured at these Rxbeams.

The cellular layer may combine the vectors to form an interferencematrix INR^(mBtk)=[INR_(mB1) ^(mBtk), INR_(mB2) ^(mBtk), . . . ,INR_(mBI) ^(mBtk)]. This may be the interference observed by the mBs(e.g., including all arrays) while mB k transmits and employs a beamrefinement procedure with mBr. The received SNR may be SNR_(mBr) ^(mBtk)at mBr).

-   -   ind=ind+1; may be looped for all possible combinations in the        database end        k=k+1, may be looped for each transmit array k        end

Output may include refined link gains between each mB, and an array Kwith the neighboring mBs. The interference matrix for one or moreneighboring mBs (e.g., all arrays) may correspond to this linkestablishment. The ordering of received powers may be used to employ afixed number of beam refinement procedures, in order to shorten theoverall link establishment period.

FIG. 11 illustrates an example mmW system 1100 with mmW mesh backhaul.The network may include several small scale base stations denoted as mBs(mmW Base stations), which may be within the coverage area of at leastone eNB. The user equipments, mUEs, may be UE's capable of operating atmmW and cellular links. In order to alleviate the operational complexityof the cellular base station for mmW control, a logical entity calledmmW Gateway, denoted as mGW in FIG. 1, may be introduced into thearchitecture. The realization of the mGW node may be achieved, forexample, by implementing it as a separate physical entity or it may beco-located with an eNB or S-GW. The mGW may provide the network withadditional wired/fiber/P2P PoP aside from the eNB, which may provideoffload of the mmW user traffic from the eNB. The eNB may be responsiblefor providing control for mmW traffic. The dense deployment ofmBs andhigh access link data rates may necessitate feasible procedures toconvey information between the mGW and mUEs. The relatively short rangeof mmW transmission due to high path-loss and penetration loss mayrequire the mBs to be deployed close to each other, which may result ina high number of mBs within the eNB coverage. For the same reasons, itmay not be realistic to establish direct physical connection betweeneach mB to the mGW. Procedures to convey information between the mGW andmUEs may be required. Mesh networking is considered, which may overcomethe burdens such as impracticality of fiber connection, requirement forlong mmW links as well as relatively wide area coverage of mmW system,etc.

A mesh backhaul routing protocol (MBRP) may be provided. Issues for therouting protocol for the backhaul (BH) may include one or more of thefollowing.

Given the necessary information regarding the networks that may becategorized as static, semi-instantaneous, and instantaneous, necessaryrouting paths may need to be provided (e.g., paths with the bestpossible performance outputs such as capacity, latency, and the like).FIG. 12 illustrates example inputs to an example MBRP).

The static or slowly changing information may be aggregated anddistributed over a large geographic area. This information, whilepossibly more global, may not capture quickly varying information. Theinstantaneous inputs may represent quickly varying information (althoughthis may include slowly varying information) and may extend to node inthe more immediate local. The categorization of the inputs may beapplication specific, and, a general classification for RNE system maybe provided.

Static Inputs may include mB node capabilities. One or more of thefollowing examples may apply: Number of antenna arrays, decode-forwardtransmission; mB locations (e.g., obtained from cellular layer); or thedesired metric to be met by the BH: capacity, delay.

Semi-Static Inputs may include one or more of the following: averagemB-mB link gains and Interference Information (e.g., obtained from asuitable BH Link Measurement Algorithm); average traffic loadreceived/transmitted by each mB; or mB antenna arrays scheduled foraccess link transmission.

Instantaneous Inputs may include one or more of the following:instantaneous channel gains/availability between mBs (and theirarrays)/Buffer status reports/possibly reports from likely extendedneighbors (e.g., 1 hop away).

MBRP decision making cases may be disclosed. The routing decisions maydepend in part on the system information availability at the cellularlayer. The overall system information can be classified as described inFIG. 12. In the following, the MBRP may be based on the cellular layerinvolvement, which may depend on the system information available ateNB.

The cellular layer may have average-term system information and mayprovide long-term routing information. For example, the statisticalinformation about the mB-mB link, e.g., the average link capacity C_(ij)(1), may be stored at the eNB. The statistical information about thetraffic may be routed through the mBs. Based on the average mB linkgains, interference matrix and average traffic load conditions, thecellular layer may provide the candidate paths (e.g., with some metrics,such as reliability). It is up to the mBs to determine which mB is totransmit in the next hop, e.g., depending on their instantaneouschannel/traffic information. For instance, a particular mB (e.g., itsarray) may be allocated for access scheduling, and may not be availablefor BH traffic.

The cellular layer may provide semi-instantaneous routing information.For example, the cellular layer may have statistical information aboutmB-mB links and the traffic routed through the mBs. The mBs may informthe cellular layer regarding the access link scheduling in advance. Thepossible routes may be updated based on the access link schedulinginformation and the mBs may be provided the updated routes. The mBs maydetermine which node to transmit, e.g., depending on the instantaneousinformation.

The cellular layer may provide instantaneous routing information. Forexample, the cellular layer may be informed about the instantaneous linkgains (e.g., measured by the mBs), traffic conditions, and/or accessscheduling. The routing decision may be made by the cellular layer andeach mB in the route may be informed.

The cellular layer overlay may allow mmW mesh routing decisions to betaken in a centralized fashion. By varying the periodicity of theparameter updates at the routing coordinator, different versions of theMBRP such as static, semi-instantaneous, and instantaneous may bepossible. Each version may have its own feedback rate and latencyrequirements on the cellular control layer.

An exemplary advantage of the cellular control layer is that it mayallow network traffic conditions to be factored into the routingdecisions via a traffic-aware route selection metric. The cellularcontrol layer may obviate the need for network flooding for routeselection. Along with a possible reduced network initialization delay,it may allow faster route adaptation after transient events like nodefailure. Centralized and decentralized MBRP may be disclosed, e.g., toshow how existing protocols can be implemented within the context ofMBRP.

A centralized routing may be disclosed. In this MBRP, a distance vectorrouting tree spanning from the mGW may be sought to be created. Here weconsider a path selection metric, e.g., Airtime Link Metric (C_(a)) usedin 802.11s standard, and show how the routing protocol may be designedaround it when directional links and a separate control layer are used.The Airtime Link Metric may be defined as follows:

$C_{a} = {\left\lbrack {O + \frac{B_{t}}{r}} \right\rbrack \frac{1}{1 - e_{f}}}$

whereO: channel access overhead including frame headers, training sequences,access protocol frames, etc.B_(t): test frame length in bits (constant)r: transmission data rate in Mbps for test frame size B_(t)e_(ƒ): test frame error/loss rate for B_(t).

A traffic-aware version of the Airtime Link Metric may include a metricsuch as time fraction (t_(ƒ)) available at a node for additionaltraffic. A new traffic-aware airtime link metric may be defined suchthat

C _(at)=ƒ(C _(a) ,t _(ƒ))

where the function ƒ(.) is independent of the enablement described next.

How the cellular assisted routing function may work for mmW directionalcommunications may be disclosed. One or more of the following may apply.

After an mB is energized the initial BH link measurement and/or neighbordiscovery may take place. At the end of the initial BH link measurementand/or neighbor discovery, the mB may have an estimate of the linkquality to each of its neighbors (e.g., either in terms of transmissiondata rate for a test frame size or in terms ofsignal-to-interference-plus-noise ratio (SNR)). There may be no loss ofgenerality in assuming already functioning neighbor mBs, which in theinitial case of the first mB joining the mesh may involve link formationwith the mGW as a neighbor, if within range. The mB may create a list ofother mB-to-mB links that may cause its SINR to a neighboring mB to dropbelow a pre-defined threshold, which may indicate potential directionalinterference. This may become a part of a black-list at the centralrouting coordinator, e.g., to avoid inter-mB interference. Theper-neighboring-mB link quality estimates and the black-list may bereported to the routing coordinator via messages on the cellular layer.

The coordinator may determine the best or an ordered set of paths backto the mGW, e.g., based on the implemented path quality metric. Sincethe neighbor mBs may be part of an already functioning mesh network, therouting coordinator may have previously evaluated the optimum paths foreach of them to reach the mGW based on their respective cumulativemetrics. Recursion of this procedure for some or all mBs may generatethe optimum multi-hop paths to the edge nodes without resorting tonetwork flooding. The routing coordinator may increment the cumulativemetrics for each of the neighbor mBs by the path metric reported by thejoining mB to determine the optimum or an ordered set of metric valuesfor the new mB. The best neighbor or an ordered set of neighbor mBidentities may be communicated to the joining mB via cellular layermessages. The metric values for each neighbor mB may be delivered to thejoining mB for use in average-term input case.

After initial route setup the mesh network operation may depend on thetype of network (e.g., static/semi-static/instantaneous), and, there maybe different procedures for each. When using average-term inputs, thecontroller may use statistical estimates of the link qualities andtraffic at each node for route determination, and subsequent updates mayinvolve statistical quantities, with minimal feedback communicationbetween the mBs and the controller on the cellular layer. The mBs maymaintain an ordered set of neighbor mBs to use for forwarding traffic,e.g., to recover from link deterioration or loss between scheduled routeupdate messages. The switch from the optimum link to an alternate may betriggered by a link deterioration determination, e.g., due to reductionin link margin on received packets, non-receipt of ACK frame from therecipient, etc. Knowledge of the link metric for alternate links mayenable the choice to switch the link due to deteriorating link margin,e.g., by comparing against the next best available value. The linkswitch may be communicated to the coordinator via a cellular layermessage, which may updates its routing tables accordingly.

The case of semi-instantaneous information may involve the mBs informingthe coordinator of their scheduling on the access link in advance, andmay not affect the routing algorithm. This case may be the same as theaverage-term case.

In the instantaneous case, a link quality estimate for each of itsneighbor mBs and traffic load may be reported by each mB to thecontroller at high frequency on the cellular layer. The link qualityestimate may be based on the observed link margin on the last receivedframe and the traffic load may be reported as the presently availabletime fraction for wireless traffic. The routing decisions from thecontroller may be conveyed to the mBs with high frequency, e.g., interms of the best next-hop node identity. The controller may transmitrouting information for an mB if it is different from the previousdecision, to decrease the control feedback traffic.

In case of node failure on the mmW channel, the affected node may notifythe routing coordinator of a failure on the cellular network, e.g., forrapid re-routing around the failure.

Decentralized routing may be disclosed. FIG. 13 is an example processflow 1300 of centralized MBRP operation. It may be described how adecentralized version of MBRP may be implemented. For this, we considerthe DMesh algorithm as an example and show how the message exchange mayoccur over two available bands: the mmW underlay and the cellularoverlay. One or more of the following may apply.

After an mB is energized the initial BH link measurement and neighbordiscovery may be performed. In the DMesh algorithm, physical treeformation may be initiated by the periodic transmission of Host andNetwork Association (HNA) messages by prospective Parent nodes on theomni-directional interface, e.g., to allow joining nodes to discoverexisting mesh nodes. In MBRP, the cellular-layer may enable efficientneighbor discovery for a joining mB. The HNA messages in MBRP may not beused for neighbor discovery, but may be used for link quality evaluationof potential first-hop links by the joining mB. The HNA messages may beperiodically transmitted by the potential next-hop neighbors identifiedpreviously (e.g., potential Parent nodes in DMesh architecture) in apre-negotiated schedule to enable the joining mB (e.g., Child node inDMesh) to evaluate individual link quality.

The joining mB may inform the chosen next-hop neighbor and/or the othercandidates of its decision via cellular layer messages. This mayindicate to the chosen next-hop mB and the other candidates that theyshould stop transmitting HNA messages. The HNA messages and the responsefrom the joining mB may include their IP addresses, which may allow thereceiving mB to associate its chosen beams, to communicate with theother mB, with the other mB's IP address. This identity, which may becalled Pointing IP address (IP), may allow IP address based filtering,e.g., so that packets received from unintended mBs via antennaside-lobes or even the main-lobe may be filtered out.

The identified Parent node may periodically transmit a READY message inthe direction of the Child node on the mmW layer. Upon successfulreception of a READY message, the joining mB may respond with a JOINmessage in the chosen neighbor mB's direction on the mmW layer, whichmay confirm link set-up. Subsequently, the chosen neighbor mB maytransmit a ROUTE_SETUP message to the eNB on the cellular layer withjoining mB's IP address, e.g., so that routing tables can be updated.

The eNB may multicast the routing table update information to routemembers along the tree from the edge mB to the mGW, e.g., via cellularlayer messages. Similarly, when an mB wants to switch parents (e.g., dueto better link quality evaluation to another mB), it may inform the eNBabout the new next-hop mB (e.g., Parent node in DMesh), and the eNB mayinform mBs along the old and the new trees to the mGW to update theirrouting tables accordingly.

FIG. 14 is an exemplary process flow 1400 of decentralized MBRP. For ageneral RNE system, the backhaul routing and access link scheduling maybe interconnected. It may be beneficial to design the access linkscheduling considering the inputs from the routing protocol. Such inputsmay be composed of but not limited to one or more of the following: thecapacity of the candidate routes; delay information along the routes;traffic load condition of the routes; and the like.

Backhaul-aware access link scheduling may provide better utilization ofaccess resources and QoS requirements. A proportional fairness metricmay be defined that may include the inputs from the BH links, QoSrequirement for the application to be transmitted to a particular mUEsuch that:

PF=ƒ(PF _(BH) ,QoS,PF _(AL))  (1)

where ƒ(.) is the composite proportional fairness matrix to bedetermined (e.g., based on the metric to be optimized), PF_(AL) isproportionally fairness metric for access link, PF_(BH) is theproportionally fairness metric for BH, and QoS is the quality of servicerequirement for the application to be transmitted to mUE. PF_(BH) is tobe determined by the backhaul conditions mentioned above.

A joint access link scheduling and BH routing protocol flow may bedisclosed, which may assume the cellular layer has the average-term linkgains. The eNB may have short term information to the other mBs in itsneighborhood. We may assume that the routing tables are alreadydetermined in either centralized or decentralized mode, e.g., asdescribed herein, and the routing table information is available at thecellular layer. One or more mUEs may already be associated withcorresponding mBs (e.g., each mUE may be assumed to be associated to onemB) and cellular layer association/configuration may already beestablished. One or more of the following may apply.

An mUE may be pinged by the cellular layer about data transmission inthe downlink. An mUE may search for mBs. Beam acquisition with thecandidate (e.g., neighboring) mBs may be employed. The cellular layermay help with the beam acquisition, e.g., the location of the mBs may beconveyed to the mUE. An mUE may obtain the channel gains (e.g., afterbeam acquisition and refinement) with respect to each candidate mB. Thisinformation may be sent to cellular layer.

Using the access link channel gain obtained above, the eNB may identifythe possible routes to the mUE from the routing table obtained above.The relative metric of each route, e.g., capacity, may be calculated.The eNB may inform one or more mBs regarding the candidate routes, forexample based on one or more average mmW channel gains. The eNB mayprovide this information to one or more mBs, for example using thecellular layer. One or more mBs may be configured to select an actualnext hop (e.g., in a route) from a candidate set. The selection may bebased, for example, on instantaneous mmW channel state information(CSI), for example as observed at an mB and/or at one or more neighbormBs.

The cellular layer may order the possible routes with respect to theirrelative metrics; e.g., Route 1>Route 2> . . . >Route N, where “>” mayrefer to having a better metric. The eNB may inform each mB on thepossible routes regarding one or more of the following: the next mBs(hops) on the routes, e.g., mB_b in Route 1; mB_c in Route 2 for mB_a;the average link gain to these mBs; the average gain between mB_a andmB_b; or the average gain between mB_a and mB_c. The mB that wishes totransmit the packet on the route may compare the instantaneous link gainwith the average link gain to the candidate mB in the selected route. Ifthe instantaneous CSI is close enough to average link gain, the packetmay be transmitted to this mB. If the instantaneous CSI is comparablyworse than Average link gain (e.g., worse than the average capacity inthe other route), another route may be selected and the above may beapplied.

Although features and elements are described above in particularcombinations, one of ordinary skill in the art will appreciate that eachfeature or element may be used alone or in any combination with theother features and elements. In addition, the methods described hereinmay be implemented in a computer program, software, or firmwareincorporated in a computer-readable medium for execution by a computeror processor. Examples of computer-readable media include electronicsignals (transmitted over wired or wireless connections) andcomputer-readable storage media. Examples of computer-readable storagemedia include, but are not limited to, a read only memory (ROM), arandom access memory (RAM), a register, cache memory, semiconductormemory devices, magnetic media such as internal hard disks and removabledisks, magneto-optical media, and optical media such as CD-ROM disks,and digital versatile disks (DVDs). A processor in association withsoftware may be used to implement a radio frequency transceiver for usein a WTRU, WTRU, terminal, base station, RNC, or any host computer.Features and/or elements described herein in accordance with one or moreexample embodiments may be used in combination with features and/orelements described herein in accordance with one or more other exampleembodiments.

What is claimed:
 1. A method for configuring a millimeter wave (mmW)mesh network, the method comprising: receiving, from a candidate nodeconfigured for millimeter wave communication, a request to join the mmWmesh network; transmitting, to the candidate node, a mesh neighborcandidate list associated with the candidate node; testing the candidatenode, in accordance with the mesh neighbor candidate list, forconformance with the mmW mesh network; and if the testing indicates thatthe candidate node conforms with the mmW mesh network, joining thecandidate node to the mmW mesh network.
 2. The method of claim 1,wherein the request is indicated in a message received from thecandidate node via a cellular access link.
 3. The method of claim 1,further comprising: receiving, from the candidate node, an mmW basestation identification associated with the candidate node; andauthenticating the mmW base station identification.
 4. The method ofclaim 1, wherein testing the candidate node comprises initiating a beamorientation procedure between the candidate node and a mesh node fromthe mesh neighbor candidate list.
 5. The method of claim 4, whereintesting the candidate node further comprises providing information tothe mesh node prior to initiating the beam orientation procedure.
 6. Themethod of claim 1, wherein testing the candidate node further comprisesdetermining at least one of signal levels between a mesh node and thecandidate node or interference levels between the mesh node and thecandidate node.
 7. The method of claim 1, wherein joining the candidatenode to the mmW mesh network comprises transmitting a notificationindicative of the candidate node joining the mmW mesh network.
 8. Anetwork device, the network device comprising: a processor configuredto: receive, from a candidate node configured for millimeter wavecommunication, a request to join the mmW mesh network; transmit, to thecandidate node, a mesh neighbor candidate list associated with thecandidate node; test the candidate node, in accordance with the meshneighbor candidate list, for conformance with the mmW mesh network; andif performance of the test indicates that the candidate node conformswith the mmW mesh network, join the candidate node to the mmW meshnetwork.
 9. The network device of claim 8, wherein the request isindicated in message received from the candidate node via a cellularaccess link.
 10. The network device of claim 8, the processor furtherconfigured to: receive, from the candidate node, an mmW base stationidentification associated with the candidate node; and authenticate themmW base station identification.
 11. The network device of claim 8,wherein the test of the candidate node comprises initiating a beamorientation procedure between the candidate node and a mesh node fromthe mesh neighbor candidate list.
 12. The network device of claim 11,wherein the test of the candidate node comprises providing informationto the mesh node prior to initiating the beam orientation procedure. 13.The network device of claim 8, wherein the test of the candidate nodecomprises determining at least one of signal levels between a mesh nodeand the candidate node or interference levels between the mesh node andthe candidate node.
 14. The network device of claim 8, wherein theprocessor is configured to transmit a notification indicative of thecandidate node joining the mmW mesh network.
 15. A method of routingcellular communications involving a wireless transmit receive unit(WTRU) configured for millimeter wave (mmW) communication, the methodcomprising: receiving, via a cellular access link, a request indicativeof transmitting data via the WTRU; performing beam acquisition with acandidate mmW base station; obtaining channel gain informationpertaining to the candidate mmW base station; and transmitting, via thecellular access link, the channel gain information to a network deviceassociated with the WTRU.
 16. The method of claim 15, wherein performingbeam acquisition comprises receiving, via the cellular access link,location information pertaining to the candidate mmW base station. 17.The method of claim 15, further comprising identifying, based upon thechannel gain information, a route for transmitting the data to the WTRUvia mmW communication.
 18. The method of claim 15, further comprisingcomparing the channel gain information to average gain informationpertaining to the candidate mmW base station.
 19. The method of claim18, further comprising, if a difference between the channel gaininformation and the average gain information is within a predeterminedthreshold, transmitting the data to the WTRU via the candidate mmW basestation.
 20. The method of claim 18, further comprising, if a differencebetween the channel gain information and the average gain informationexceeds a predetermined threshold, transmitting the data to the WTRU viaa second mmW base station that is different from the candidate mmW basestation.